Description
In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect. This affects only HTTP/2 connections. A possible mitigation is to not enable the h2 protocol.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.17 to 2.4.34 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | apache2 | 2.4.35-1 | — |
| Debian 13 | apache2 | 2.4.35-1 | — |
| Debian 12 | apache2 | 2.4.35-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | apache2 | 2.4.29-1ubuntu4.4 | USN-3783-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 3 | httpd24-curl +2 | 7.61.1-1.el6 | RHSA-2018:3558 |
| RHEL 3 | httpd24-httpd +5 | 2.4.34-7.el6 | RHSA-2018:3558 |
| RHEL 3 | httpd24-mod_md | 2.4.34-7.el7 | RHSA-2018:3558 |
| RHEL 3 | httpd24-mod_ssl +1 | 1:2.4.34-7.el6 | RHSA-2018:3558 |
| RHEL 3 | httpd24-nghttp2 +2 | 1.7.1-7.el6 | RHSA-2018:3558 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Core Services 1 | jbcs-httpd24 +1 | 1-6.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apache-commons-daemon-jsvc | 1:1.1.0-3.redhat_2.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apr +1 | 1.6.3-31.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apr-util +8 | 1.6.1-24.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.29-35.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_cluster-native | 1.3.8-3.Final_redhat_2.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_jk +2 | 1.2.46-1.redhat_1.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.29-35.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-nghttp2 +1 | 1.29.0-9.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.0.2n-14.jbcs.el6 | RHSA-2019:0367 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 | apache2 | 2.4.33-3.6.1 | SUSE-SU-2018:3101-1 |
| SLES 12 SP4 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-2 |
| SLES 12 SP3 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-1 |
| SLES 12 SP2 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP4 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-2 |
| SLES for SAP 12 SP3 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-1 |
| SLES for SAP 12 SP2 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-1 |
| SUSE OpenStack Cloud 7 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-1 |
| SUSE Enterprise Storage 4 | apache2 | 2.4.23-29.27.2 | SUSE-SU-2018:3582-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | virtualbox | 6.1.26-3.2 | openSUSE-SU-2024:11501-1 |
| openSUSE Leap 15.1 | virtualbox | 6.0.10-lp151.2.6.1 | openSUSE-SU-2019:1814-1 |
| openSUSE Leap 15.0 | virtualbox | 5.2.24-lp150.4.33.1 | openSUSE-SU-2019:1814-1, openSUSE-SU-2019:1547-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | apache2 | 2.4.35-r0 | — |
| Alpine v3.23 | apache2 | 2.4.35-r0 | — |
| Alpine v3.22 | apache2 | 2.4.35-r0 | — |
| Alpine v3.21 | apache2 | 2.4.35-r0 | — |
| Alpine v3.20 | apache2 | 2.4.35-r0 | — |
Show 15 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | apache2 | 2.4.35-r0 | — |
| Alpine v3.18 | apache2 | 2.4.35-r0 | — |
| Alpine v3.17 | apache2 | 2.4.35-r0 | — |
| Alpine v3.16 | apache2 | 2.4.35-r0 | — |
| Alpine v3.15 | apache2 | 2.4.35-r0 | — |
| Alpine v3.14 | apache2 | 2.4.35-r0 | — |
| Alpine v3.13 | apache2 | 2.4.35-r0 | — |
| Alpine v3.12 | apache2 | 2.4.35-r0 | — |
| Alpine v3.11 | apache2 | 2.4.35-r0 | — |
| Alpine v3.10 | apache2 | 2.4.35-r0 | — |
| Alpine v3.9 | apache2 | 2.4.35-r0 | — |
| Alpine v3.8 | apache2 | 2.4.35-r0 | — |
| Alpine v3.7 | apache2 | 2.4.35-r0 | — |
| Alpine v3.6 | apache2 | 2.4.35-r0 | — |
| Alpine v3.5 | apache2 | 2.4.35-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | httpd +7 | 2.4.37-1.amzn2.0.1 | ALAS2-2019-1155 |
| Amazon Linux 2 | mod_http2 | 1.11.1-1.amzn2 | ALAS2-2018-1104 |
| Amazon Linux 2 | mod_ssl +1 | 1:2.4.37-1.amzn2.0.1 | ALAS2-2019-1155 |
Advisories 12
- RHSA-2019:0367 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.29 security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2018:3558 Red Hat Security Advisory: httpd24 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- USN-3783-1 apache2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- openSUSE-SU-2019:1547-1 Security update for virtualbox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:3101-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:1814-1 Security update for virtualbox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11501-1 python3-virtualbox-6.1.26-3.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:3582-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:3582-2 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-1682 Oracle Retail Applications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 21, 2024
- ALAS2-2019-1155 Moderate: httpd security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jan 25, 2019
- ALAS2-2018-1104 Moderate: mod_http2 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 8, 2018
References
- https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.html
- RHSA-2018:3558 vendor-advisory
- 105414 vdb-entry
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03909en_us
- https://security.netapp.com/advisory/ntap-20190204-0004/
- RHSA-2019:0367 vendor-advisory
- USN-3783-1 vendor-advisory
- https://httpd.apache.org/security/vulnerabilities_24.html
- 1041713 vdb-entry
- RHSA-2019:0366 vendor-advisory
- https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
- openSUSE-SU-2019:1547 vendor-advisory
- openSUSE-SU-2019:1814 vendor-advisory
- [httpd-cvs] 20190815 svn commit: r1048743 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20190815 svn commit: r1048742 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- https://www.tenable.com/security/tns-2019-09
- [httpd-cvs] 20200401 svn commit: r1058586 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058587 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073143 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073140 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.ht mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [11/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1888194 [11/13] - /httpd/site/trunk/content/security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [11/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [httpd-cvs] 20210606 svn commit: r1075470 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list